What a well-intentioned friend may see as a clear-cut problem with an obvious solution -- an anorexic should eat more, for example, or a compulsive shopper should cut up the credit card -- is something far more complex.

This helps to explain the individual's resistance to change -- which frustrates those who try to intervene.

"Friends feel powerless because they are," Wurtzel says. "These compulsions have roots in issues that have taken a lifetime to develop."

"A friend can offer support, but finding the reasons behind the behavior, and breaking down resistance? That's a therapist's job," Wurtzel says.

Setting boundaries

When the friend you're trying to help can't let go, should you?

"I had to," says Michael, whose attempts to help a friend spiraling out of control after her mother's death were thwarted repeatedly.

"It started with drinking and drugs, then she quit her job, canceled her cell phone, just dropped off the map -- like an animal that goes off to die," says the IT technician living outside of Washington, DC.

Michael, who asked that his full name not be used, said he wanted to help "but in my experience, helping someone who's not ready pushes them away -- and makes you worse, because nothing you do makes a difference."

Michael's friend ultimately sought professional help, but they're no longer close. Theresa has lessened contact with her friend.

Despite good intentions, some helpers may be overly invested in fixing friends who can't seem to fix themselves.

"I definitely attract needy people," says Theresa. "When I was able to help (the friend), it felt good -- but that became harder and harder, and she'd blame me for letting her down."

"It's much easier to focus on another's problems than to acknowledge our own," says Wurtzel, who works with patients who repeatedly seek out helper-helpee relationships. "And this can become its own compulsion, recreating a familiar dynamic that's just as self-destructive for the helper."

"If you're compelled to intervene in these situations, ask yourself what you're getting out of it," Wurtzel says.

Finding a balance

According to Wurtzel, the key to helping a self-destructive friend lies in a delicate balance of compassion and boundaries. She offers advice for lending a hand while preserving the friendship -- and your sanity:

• Set expectations, but don't make demands. "An adult relationship is based on expectations, standards and values, with compassion for differences," Wurtzel says. "Demanding the other do things for you and the relationship creates a power struggle."

• Make the other feel heard. "People with self-destructive tendencies expect others to be angry with and abandon them," says Wurtzel. "You can validate their difficulties without condoning the behavior."

• Understand your powerlessness. "If you feel powerless in the situation, it's because you are," Wurtzel says. "The battle of self-destructive behavior is within the person, between them and them."

• Resist the rescue impulse. If someone's always swooping in to save the day, the self-destructive person has no reason take care of themselves. "Lay out your expectations for the relationship, for what you're willing to do and what you expect them to do," Wurtzel says. "It creates the impetus to change."

• Set boundaries -- not for the self-destructive person but for yourself. "Otherwise the relationship becomes unequal, unhelpful and destructive to both people," Wurtzel says.E-mail to a friend

LifeWire provides original and syndicated lifestyle content to Web publishers. E. Bougerol is a writer in New York City.